


You Promised!

by scarletmanuka



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: M/M, Outdoor Sex, Prompt Fill, Sibling Incest, Smut, holmescest
Language: English
Status: Completed
Published: 2017-11-07
Updated: 2017-11-07
Packaged: 2019-01-30 17:31:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,835
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12658164
Author URL: https://archiveofourown.org/users/scarletmanuka/pseuds/scarletmanuka
Summary: Based on the prompt: Sherlock is standing on a balcony, naked, smoking a cigarette; you only see him from behind. Mycroft is watching him from inside the room. What is the story behind?





	You Promised!

**Author's Note:**

  * For [LadyGlinda](https://archiveofourown.org/users/LadyGlinda/gifts).



Flipping the light switch as he exited the bathroom, Mycroft’s eyes scanned the hotel room, looking for his brother. The curtains were fluttering gently in the breeze and he stepped closer to see Sherlock already standing naked on the balcony, a cigarette in hand as he gazed out over the darkened resort. He took a deep drag, tilting his head back to blow the smoke into the night sky, exposing the long column of his throat as he did so. The moonlight gave the younger man’s skin a bluish tinge, the pale expanse of his legs and back seeming to almost glow. Mycroft’s fingers itched to touch him, to map out the lean planes of his body but his fear held him back.

“Are you going to hide inside forever?” Sherlock called after another minute had passed.

“This is really a terrible idea,” Mycroft muttered, but his voice carried and his brother heard him.

“My, you  _ promised _ !”

“I know, but to be fair, you were doing that thing with your tongue when you asked so I wasn’t strictly in my right mind at the time when I agreed.”

He heard the curly haired detective huff through the open door. “If you ever want me to do that thing with my tongue again, then you’ll get your arse out here right now and do what you said you would!”

“I never took you for the blackmailing sort, brother mine.”

“Really? I wanted to be a pirate, My - I really thought that would have given my views on blackmail away from an early age, or at the very least my skewed moral compass.”

“Perhaps I was merely hoping that my good influence would have rubbed off on you?”

“Something of yours has rubbed off on me but it’s  _ not _ been your good influence. Now stop being such a worry wort and get out here!”

“Do I really need to point out -  _ again _ might I add - that if we are seen, we will not only likely be charged with public indecency, but it will let the cat out of the bag about the true nature of our relationship?”

Sherlock seemed to grow tired of bickering through the open door and he stalked inside, moving like an animated marble statue through the moonlit room. “There is far less risk involved than you seem to think, My,” he said, taking Mycroft’s hands in his own.

“It’s easy to say that now, but how will you feel if a report detailing what we were doing passed across Lestrade’s desk?”

“It won’t, I promise it won’t! The lights are off so we won’t be back lit, it’s 3am and no one is stirring out there, and even if someone  _ is _ awake, if they’re on their own balcony they would have to be a contortionist to see into ours. The only way anyone would see us is if there really  _ are _ pirates out on that ocean and they  _ happen _ to be spying this way at exactly the right time.” He lifted their joined hands to his lips and kissed them softly. “Please, My?  _ Please _ ?” he wheedled. “Please fuck me outside?”

Mycroft felt himself giving in. Sherlock had been so excited about the prospect of semi-public sex, and it had been easy enough to agree at the time. His brain had been buzzing since, reminding him of all the ways it could go horribly wrong, but who was he even trying to convince at this point? Everyone knew he would do  _ anything _ for Sherlock, even if they didn't quite know the extent of his devotion. If Sherlock asked him to have sex in the frozen food aisle of Tesco, Mycroft had no doubt that after a handful of protests, he would eventually give in as well if it was what his brother really wanted. Of course he wasn’t going to be mentioning  _ that _ tidbit to his brother, otherwise he had no doubt he would be discovering what Sherlock looked like while having an orgasm next to the microwavable dinner selection.

“Fine,” he relented. “ _ But _ you have to promise to be quiet, Sherlock.” He held up a hand to silence the whoop of joy already forming on that lovely Cupid’s bow. “I mean it! The second one of those sinful moans of yours projects past the balcony railing, I’ll pull out of you and be inside before your sphincter has stopped fluttering. Understand?”

“Yes, yes I promise,” Sherlock cried, pulling Mycroft to him by the back of his neck and crashing their lips together. 

Unable to help himself when faced with such overwhelming enthusiasm, Mycroft eagerly returned the kiss. Sherlock’s nimble fingers worked at the tie on the front of the gown the older man wore and soon it was being slipped off his shoulders to pool in a puddle at his feet. Still caught up in the kiss, they began to move towards the open door, the curtains gently slapping against their legs in the breeze as they moved past them.

It took everything Mycroft had to not flinch as they stepped out onto the balcony, exposing themselves to the cool night air for the first time. He had to put trust in Sherlock’s reasoning that it was very unlikely they would be spotted, yet still he fought the urge to crouch down behind the small outdoor setting where they ate their breakfast as they watched the sun rise over the waves. Sherlock broke the kiss and turned around, stepping forward and leaning against the railing, presenting his plush arse to Mycroft. The glimmer of hope Mycroft had had that he could convince his younger brother to stay close to the wall faded and he swallowed hard as he saw Sherlock’s erect penis sticking right through the gap in the railing, pointing proudly out to sea. With a sultry look over his shoulder, Sherlock beckoned him closer.

“I didn't bring any lube,” Mycroft muttered, unable to help himself as his hands trailed down Sherlock’s spine before taking two handfuls of his brother’s arse and kneading the flesh firmly.

“Don’t need it, I’m already prepared,” the younger man replied, pushing against the hold Mycroft had on him.

“Oh really?” Sliding a finger down his crack, Mycroft felt the slippery wetness of the lube that had been liberally applied and his own cock jumped in response. Without hesitating any further, he nudged Sherlock’s legs apart and slotted himself up against him, guiding his cock to the welcoming entrance. It took a couple of attempts due to the angle but shortly Mycroft was pushing into the tight heat of his baby brother’s arse, neither of them able to contain the gasps of pleasure they both felt. Needing to be deeper as soon as possible, Mycroft grabbed hold of Sherlock’s hips and pulled him down, impaling him on his shaft until he had bottomed out. Sherlock’s head tipped back in ecstasy, resting on his brother’s shoulder and Mycroft promptly attached his lips to the exposed skin, worrying a small bruise into the pale flesh.

After a moment where they both adjusted to the sudden assault on their senses, Mycroft began to rock his hips, thrusting shallowly upwards. The younger man gripped the railing hard, using it as leverage to push himself back and down. His eyes were closed, long lashes fluttering against his cheeks and Mycroft kissed his ear gently and whispered, “Open your eyes, love. No point in making love outside if you’re not going to take in the view.”

Sherlock’s eyes fluttered open and he straightened a little so he could look forward. In reality, they couldn't see much of the ocean beyond the odd light on the perimetre of the resort, but to their right was the pool area, brightly lit but deserted, the lazy river gurgling quietly between the deeper pools. During the day the area teemed with guests, and it was easy to imagine a crowd only a short distance away, unaware of the lustful act going on just above them.

Sherlock shuffled his feet, his stance widening and he gasped loudly as the change in position allowed Mycroft’s cock to nudge against his prostate. The older man growled against his ear, a warning to be quiet even as he thrust again, hoping to hit the same spot. When he hit the bullseye again and Sherlock cried out, Mycroft reached a hand up to clamp over his brother’s mouth, effectively silencing him. The detective’s back arched and one of his hands reached wildly for his own cock, grabbing it and beginning to stroke it hard and fast. His lips moved against Mycroft’s palm, a string of unintelligible babble trying to escape but unable to. Mycroft rocked his hips again and again, bushing over that sensitive bundle of nerves as often as he could. Sherlock’s pale hand flew over his cock and then his whole body stiffened and he bit down hard on Mycroft’s hand to stop the cry that came from his mouth as he pumped hot semen out through the gap in the railing and into the night air. 

As his brother slumped back against him, spent from his orgasm, Mycroft continued to thrust into him, chasing his own release. He’d been close, so close, but the sting of pain from the bite had taken the edge off and he had to work to get there once more. It was the sounds of voices coming from a balcony somewhere to their left that was the catalyst - proof that they weren’t the only ones awake at this early hour of the morning. The thrill of danger that shot through him seemed to travel directly to his cock and he buried his face into the crook of Sherlock’s neck to muffle his own sounds of release as he pumped his brother’s arse full of his own load. 

They stood together, panting quietly, the breeze cooling their sweaty skin, listening to the couple nearby point out several constellations they recognised and then comment on how quiet the night was. Eventually they decided to go back to bed and when the distinct  _ click _ of their door closing sounded, Mycroft allowed his rapidly softening cock to slip entirely out of Sherlock. His brother made a small sound of discomfort as lube and come dripped down his thigh and turned to face Mycroft. “Shall we head inside and clean up?”

Mycroft couldn’t help but smirk. “So eager to bring your moment of exhibition to an end, hmm?”

“Yes, well, as much as I enjoyed it, I’m mature enough to admit that I can appreciate the convenience of having the bathroom closer to hand.”

“Fair enough, love. But in all seriousness, was it like you’d hoped?”

“Oh, My,” Sherlock said, pulling him in for a kiss. “It was even better. Thank you for granting me this silly wish.”

“Sherlock, I’d do anything for you, don’t you know that by now?”

“Anything?”

“Of course. Why?”

“Well, there is this one fantasy I have about the frozen food aisle in Tesco…”

  
  
  
  



End file.
